FDA: Levemir insulin now safe for pregnancy

To maximize the chances of having a healthy baby, women who are pregnant with pre-existing diabetes need to keep very tight control of their blood sugar levels. To do so, many begin taking insulin, sometimes for the first time if they are type 2, before or early into their pregnancies.

Now there's a new option for those who inject.

Levemir, an insulin that works to keep blood sugars steady for up to 24 hours at a time, was recently approved by the United States Food and Drug Association (FDA) as a category B medication. The insulin, also known by its generic name detemir, is the first basal (long-acting) insulin to receive this approval; category B drugs are those that do not increase the risk of harm to a growing fetus.

According to a press release, the FDA category change was based on a review of a large, randomized controlled trial of 310 pregnant women who used either Levemir or NPH insulin. The study found that those who took Levemir had similar A1C levels at gestational week 36 and lower fasting blood glucose levels at gestational weeks 24 and 36, compared with NPH. Additionally, Levemir was considered safe for the women, both during pregnancy as well as after delivery, both for mother and child. The research is pending acceptance for publication, but was presented in 2011 at the American Diabetes Association's 71st annual Scientific Sessions.

"The approval of insulin detemir is the best advance that has happened for the field of diabetes and pregnancy since the discovery of insulin," said Dr. Lois Jovanovic, MD, MACE, the Chief Scientific Officer of the Sansum Diabetes Research Institute in Santa Barbara, California.

Levemir, manufactured by Novo Nordisk, begins working in the body 2-4 hours after injection, and doesn't peak. It provides a steady dose of long-acting insulin for twelve hours. Before the FDA approval of Levemir, doctors typically prescribed NPH insulin, also a category B drug, for pregnancy.

However, NPH is an intermediate-acting insulin; it begins working 1-2 hours after injecting and works over eight hours. It is most effective between four and eight hours after injecting, which can cause low blood sugars in the middle of the day. Both Levemir and NPH are typically prescribed at bedtime, but NPH needs to be taken at midnight if women want to sleep until 7 or 8 am the next morning, when they need to take another dose, said Jovanovic. Lower blood sugars are always a concern, she said, and using NPH "forces women to watch the clock. Levemir means that they can delay lunch and not worry about hypoglycemia," she said. "The three injections of NPH must be perfectly timed 8 hours apart and thus NPH adds another chore for the women while they do all of their other self care needs. Levemir 'cures' the worry and facilitates achieving around the clock" blood sugar control.

"Women can now take their evening insulin and not worry about staying up until midnight to take the NPH injection," Jovanovic said. "There is no worry that the bedtime dose of basal insulin will be missed by a sleepy pregnant woman."

Skipping insulin doses causes blood sugar levels to rise to levels that can be dangerous to both the mother and developing child. Missing a bedtime dose of NPH could mean that a woman would develop ketoacidosis overnight, and ketoacidosis increases the risk of fetal death, said Jovanovic.

Ketoacidosis occurs when there isn't enough insulin in the body to convert glucose into energy, so the body processes fat for energy and develops an acid called ketones.

Safety data for Levemir

Others are more cautious about introducing Levemir to their pregnant patients. "I am interested in learning more about how the FDA made its decision," said Florence Brown, M.D., the co-director of the Diabetes in Pregnancy Program at the Joslin-Beth Israel Deaconess Medical Center in Boston, Massachusetts. "I have not seen safety and efficacy data yet published in a peer-reviewed journal."

Brown said she wanted to know that Levemir would not cause more serious high or low blood sugar levels during pregnancy, and that it didn't contribute to issues such as preeclampsia, preterm delivery, or babies born with low blood sugars or higher birthweights.

"Before I start using Levemir, I will want to see data that shows that Levemir is just as safe and just as effective as NPH insulin, which is currently the preferred basal insulin for women who take insulin injections," Brown said.